You might have a look at a list of analogous questions (questions asking for open problem lists), to see which ones were well-received and why:

http://mathoverflow.net/search?q=open+problems

For example:

open problems in Seiberg-Witten Theory on 4-Manifolds

If you keep it focussed, then a request for an open problem list makes a decent big-list question, I think.

You might have a look at a list of analogous questions (questions asking for open problem lists), to see which ones were well-received and why:

https://mathoverflow.net/search?q=open+problems

For example:

open problems in Seiberg-Witten Theory on 4-Manifolds

If you keep it focussed, then a request for an open problem list makes a decent big-list question, I think.